Moments after discovery, an inscribed fragment of an ancient clay cylinder is lifted from the ground to be photographed. One hand holding the fragment points, with the small finger, to the cuneiform characters for “Mashkan-shapir,” the name of the Mesopotamian city that flourished at this site from about 2050 to 1720 B.C. American archaeologists excavating at Mashkan-shapir, in Iraq, will probe the city’s manufacturing centers, temples, palace, cemetery and elaborate canal system linked to both the Tigris and Euphrates rivers.